Organic produce has tentatively been determined to be behind an E. Coli outbreak that has sickened children in the Seattle-King County area in Washington State.

“Our investigation is ongoing. We have identified multiple types of fresh produce, mostly organic, in common among the majority of cases but cannot yet rule out other possibilities,” the health department reported in its outbreak update.

“Public Health is conducting interviews with cases and their parents/guardians to help identify any common exposures. We are also working with the Washington State Department of Health to complete further testing, to help identify possible related cases in other counties, and to begin traceback of any products in common.”

The health department is warning consumers that fresh fruits and vegetables — including organics — can sometimes have germs such as E. Coli on them. The contamination of such foods has been implicated in numerous outbreaks in recent years. The department encourages consumers to thoroughly rinse fresh produce before preparing and consuming it raw.

All of the patients are younger than 15 years of age, and three are younger than 5 years of age. The seven patients have been reported during April 22-May 1 time period, according to Seattle-King County Public Health.

Six of the children have been so sick they had to be admitted to hospitals. This includes two children who developed a potentially life-threatening type of kidney complication called hemolytic uremic syndrome (HUS). Both are recovering.

Investigators are continuing their work on the outbreak and will post updates as new information becomes available.